Today's large scale computer rooms typically employ human technicians which manually load magnetic data storage media (e.g. magnetic tape spools) onto computer drives. With the recent advent of computer tape cassettes (i.e., as represented by the IBM 7575 system), the space requirement for physically cataloging and storing the magnetic media has decreased (due to the decreased size of these tape cassettes as compared to the more conventional magnetic tape spools).
However, human intervention is still typically required when a tape cassette must be removed from, or inserted into, a computer's tape drive. Thus, it would be highly advantageous if an automated system was provided which was capable of retrieving a cassette from a library/storage location, transporting the cassette to a drive unit associated with the computer system, and then inserting the cassette into the drive unit. Such an automated system could also suitably be employed in a variety of other end use applications (i.e., other than in the context of a computer mass data storage facility), such as in radio and/or television broadcast stations whereby preprogrammed tape cassettes could automatically be retrieved from a library location and inserted into suitable playback equipment. Those in the art will undoubtedly appreciate other uses for the invention after considering the following description thereof. It is therefore towards attaining such an automated system that the present invention is directed.
The present invention achieves the advantages mentioned above by providing a complete system which is capable of moving an article (e.g., a data storage cassette) between a cassette library site and a cassette drive unit. To achieve this function, the robot system of the present invention includes a track which establishes a path of conveyance for the system between the cassette library and drive unit. A carriage assembly is coupled to the track and is capable of movements therealong by virtue of the meshed interengagement between a driven pinion gear (associated with the carriage assembly) and a gear rack (associated with one of the track members).
A robot is supported upon a platform which is coupled to a vertical column of the carriage assembly for slidable reciprocal movements between extreme lowered and raised positions (and any position intermediate these extremes). The platform (and hence the robot supported thereupon) is driven between these lowered and raised position by means of an endless flexible drive member (e.g., an endless chain) which is drivenly connected to a suitable reversible electric motor via a drive sprocket. Therefore, upon operation of the electric motor in one or another of its rotational directions, the platform (and hence the robot supported thereupon) is capable of being selectively displaced vertically between its raised and lowered positions, respectively. The transport system of this invention may thus assist in positioning the robot adjacent one of the separate equipment components with which it interacts (e.g., adjacent the cassette library or cassette drive unit), and moreover, may move the robot between that component and another one of the components so that it may then interact with the latter component.
The robot is provided with a manipulator hand which is especially adapted to grip and release a data storage cassette. The manipulator hand is, moreover, especially adapted to interact not only with the cassette, but also with the cassette drive unit, and more particularly, with an input slot of the drive unit.
More specifically, the manipulator hand includes a pair of finger members which collectively establish a space therebetween for accepting the cassette and which are relatively moveable between a gripped position (wherein the cassette is gripped between the finger members) and a released position (wherein the cassette is released from its gripped relationship with the finger members).
A mechanical ejector is also preferably provided so as to insure that the cassette is positively removed from the manipulator hand when the fingers thereof are relatively moved into their released position. This mechanical ejector is preferably embodied in a generally U-shaped ejector member having a forward end which engages the cassette when the robot manipulator is advanced to grip the cassette. Upon this advancement, the ejector member is retracted (due to its mounting structures to be discussed below) against the urging force of a pair of compression springs.
The finger members thus are relatively moved so as to grip the article when the robot manipulator has been advanced sufficiently. At the same time, the ejector member is "loaded" due to the compression of its springs. Therefore, when the finger members release the cassette, this "loaded" force will drive the ejector member forwardly to responsively eject the cassette from the robot manipulator. In this manner, the ejector member ensures that the cassette will not "hand" onto the finger members.
The robot manipulator also preferably includes a push rod which extends rearwardly in a direction opposite to the finger members. This push rod is especially adapted to physically push the tape cassette into its final operative position within the tape drive. Also, the push rod serves to engage a movable door associated with a slot on the tape drive. When the push rod engages the opened door (i.e., after the robot manipulator has initially inserted a cassette into the drive unit's slot and after the push rod has seated the cassette into the drive unit), the entire robot manipulator is then moved in a downwardly direction, so that the manipulator thus serves the additional beneficial function of closing the drive unit's door to thereby place it in operation.
Means are also provided to ensure that mechanical shocks to the manipulator are absorbed. In this regard, the entire housing of the manipulator is mounted upon guide rails which allow it to be displaced rearwardly when the finger members experience a shock (as by imprecise alignment between the finger members and the equipment with which they interact). A shock spring urges the robot hand into its forward-most position, yet resiliently cushions its rearward movement relative to the guide rails when a shock is experienced, thereby damping the same. A spring-based shock absorbing assembly is also in operative association with the push rod to accomplish similar shock-absorbing functions.
In many end use environments, it will be necessary to pivot the finger members between first and second planar orientations--particularly, for example, if the cassettes are physically stored at a library location in a vertical orientation, but are inserted into/removed from the drive unit in a substantially horizontal orientation. To compensate for this need, the present invention includes structure which permits the finger members to be pivoted between these first and second planar orientations. In this regard, the housing for the robot manipulator is mounted (a) for vertical movements between raised and lowered positions, (b) rotational movements between first and second positions, and (c) lateral movements between initial and final positions. A platform is also provided which establishes a bearing surface and is disposed in a fixed-position with respect to these housing movements.
A cylindrical engagement surface and a locking assembly are each provided in operative association with the housing. When the housing moves into its lowered position, a terminal end of the locking assembly contacts the bearing surface to thereby unlock the housing to allow it to freely rotate between its first and second positions. At the same time (i.e., with the housing in its lowered position), frictional engagement occurs between the cylindrical engagement surface and the bearing surface. This frictional engagement thereby provides the means for rotating the housing between its first and second positions when the housing is laterally moved from its initial position to its final position.
Further aspects and advantages of this invention will become more apparent to the reader after careful consideration is given to the detailed description of the preferred exemplary embodiment thereof which follows.